The foot provides support for the rest of the body when the body is in the erect position. The big toe assists in this support. The first metatarsal phalangeal joint of the big toe is the point of maximum propulsion of the foot and must be capable of 60.degree.-75.degree. dorsi flexion for normal ambulation.
Unfortunately, bunions (Hallux Valgus), are often formed on the first metatarsal phalangeal joint and may affect ambulation. A bunion is a condition which is defined as inflammation and pain associated with osseous hypertrophy of the first metatarsal head forming a medial eminence which may be associated with lateral deviation of the first metatarsal phalangeal joint. Although generally hereditary, bunions can be exacerbated by poor-fitting footwear.
Bunions can be excruciatingly painful. Bunion sufferers often therefore avoid certain activities and try to avoid wearing shoes as much as possible, both because of the pain and because it is extremely difficult to find footwear which will accommodate the bunion. Bunion sufferers may also compensate by changing the way they walk in order to alleviate the pain and discomfort. Such changes are unnatural and cause their movements to be inefficient causing strain on the body parts too heavily relied upon. When a sufferer tires of living with constant pain, he or she may seek medical advice for definitive treatment of his or her bunions.
The treatment of bunions has historically ranged from symptomatic relief to surgical procedures involving removal of the bunion and realignment of the first metatarsal phalangeal joint. In most cases, surgery is critical to long-term relief of pain and improvement of ambulation. Bunionectomies are a common osseous procedure. In addition to bunions, other conditions of the first metatarsal phalangeal joint may require surgery. Such conditions might include Hallux Rigidus/Limitus; Osteoarthritis and Traumatic Arthritis; Hallux Abducto Valgus; Traumatic Crush Injury; and conditions precedent to open reduction of fractures of the first metatarsal phalangeal joint.
Following surgery on the metatarsal phalangeal joint, the joint must recover and be rehabilitated. Immobilization or rest of recovering joints has long been an unchallenged tenet of orthopedics. The effects of immobilization have been widely reported. Muscular atrophy and joint stiffness are, by far, the most obvious side effects of immobilization. Bone atrophy also results from immobilization and it appears logical to assume that other musculoskeletal structure including tendons, ligaments and collagen matrix will also atrophy when they are protected from the stimulus of physiological loading.
Continuous passive motion (CPM) contributes more to joint rehabilitation following surgery than immobilization. It helps assure a good surgical outcome by improving the joint's rate of healing and decreasing the possibility of limited range of motion after healing is completed. Range of motion is a critical parameter of joint healing and patient recovery. CPM contributes greatly to improved ambulation. The clinical advantages of continuous passive motion, as compared with immobilization, are providing earlier motion, achieving functional range of motion earlier, achieving a greater ultimate range of motion, decreasing postoperative pain and swelling, prevention of intra-articular adhesions and extra-articular contractures, and decreasing the incidence of deep venous thrombosis by improving venous dynamics. In spite of widespread recognition of the advantages of continuous passive motion over immobilization, no prior devices provide continuous passive motion to the first metatarsal phalangeal joint, isolation of which is critical following surgery thereon.
Accordingly, there has been a need for a novel continuous passive motion device which is light weight for portability, and operates smoothly and relatively silently. Such a device is needed which can run unattended, allows for altering the range of motion appropriate for each patient, is easy to use with a patient-controlled on/off switch, and can be used in the hospital or at home. Additionally, a continuous passive motion device for the first metatarsal joint is needed which may be used sitting or in a supine position, is easily cleaned and stored, able to take the affected toe through its full range of motion, easily adjusts from left to right foot and vice versa, and accommodates different foot sizes. The present invention fulfills these needs and provides other related advantages.